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| author | Guenter Roeck <linux@roeck-us.net> | 2019-04-05 18:53:08 +0300 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2019-05-31 16:47:27 +0300 |
| commit | ba684158094c6bbca7f194227e58d2a7a491c9fd (patch) | |
| tree | 452947f380b2f9c992ee8d1b78890bb38b452f5a /drivers/hwmon | |
| parent | ffa61ab75cfabf9d6eafeed37b7bea88218870ad (diff) | |
| download | linux-ba684158094c6bbca7f194227e58d2a7a491c9fd.tar.xz | |
hwmon: (vt1211) Use request_muxed_region for Super-IO accesses
[ Upstream commit 14b97ba5c20056102b3dd22696bf17b057e60976 ]
Super-IO accesses may fail on a system with no or unmapped LPC bus.
Also, other drivers may attempt to access the LPC bus at the same time,
resulting in undefined behavior.
Use request_muxed_region() to ensure that IO access on the requested
address space is supported, and to ensure that access by multiple drivers
is synchronized.
Fixes: 2219cd81a6cd ("hwmon/vt1211: Add probing of alternate config index port")
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Diffstat (limited to 'drivers/hwmon')
| -rw-r--r-- | drivers/hwmon/vt1211.c | 15 |
1 files changed, 12 insertions, 3 deletions
diff --git a/drivers/hwmon/vt1211.c b/drivers/hwmon/vt1211.c index 3a6bfa51cb94..95d5e8ec8b7f 100644 --- a/drivers/hwmon/vt1211.c +++ b/drivers/hwmon/vt1211.c @@ -226,15 +226,21 @@ static inline void superio_select(int sio_cip, int ldn) outb(ldn, sio_cip + 1); } -static inline void superio_enter(int sio_cip) +static inline int superio_enter(int sio_cip) { + if (!request_muxed_region(sio_cip, 2, DRVNAME)) + return -EBUSY; + outb(0x87, sio_cip); outb(0x87, sio_cip); + + return 0; } static inline void superio_exit(int sio_cip) { outb(0xaa, sio_cip); + release_region(sio_cip, 2); } /* --------------------------------------------------------------------- @@ -1282,11 +1288,14 @@ EXIT: static int __init vt1211_find(int sio_cip, unsigned short *address) { - int err = -ENODEV; + int err; int devid; - superio_enter(sio_cip); + err = superio_enter(sio_cip); + if (err) + return err; + err = -ENODEV; devid = force_id ? force_id : superio_inb(sio_cip, SIO_VT1211_DEVID); if (devid != SIO_VT1211_ID) goto EXIT; |